1. Field of the Invention
The present invention relates to an actuator which allows a slider to perform a rectilinear reciprocating motion along a frame under the driving action of a driving source.
2. Description of the Related Art
A transport means such as an actuator has been hitherto used, for example, in order to transport a workpiece.
A conventional actuator is shown in FIGS. 15 and 16 (see, for example, Japanese Laid-Open Patent Publication No. 11-30234).
The conventional actuator 1 includes a slider 4 which is displaceable along a recess 3 of a track rail 2, and a screw shaft 6 which is driven by an unillustrated driving motor and which is screwed together with a nut member 5 that is detachable with respect to the slider 4. Screw shaft supports 7a, 7b, which rotatably support the screw shaft 6, are provided at both ends of the screw shaft 6. The screw shaft supports 7a, 7b are attached on an upper surface 8 of the track rail 2.
However, in the conventional actuator 1 as described above, the slider 4 is displaced by converting the rotary motion of the screw shaft 6 into the rectilinear motion of the slider 4 by nut member 5. Therefore, even if the screw shaft 6 is rotated at a high speed, it is difficult to greatly increase the displacement speed to displace the slider 4 at a high speed.
Further, there is a demand to realize an actuator smaller in size and lighter in weight to meet the installation requirements of individual users.